[Intel-gfx] [PATCH 2/2] drm/i915/execlists: Pack the count into the low bits of the port.request

[Chris Wilson]

On Fri, Mar 31, 2017 at 03:10:33PM +0100, Chris Wilson wrote:
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
> index a82a0807f64d..51497653c830 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> @@ -373,8 +373,12 @@ struct intel_engine_cs {
>  	/* Execlists */
>  	struct tasklet_struct irq_tasklet;
>  	struct execlist_port {
> -		struct drm_i915_gem_request *request;
> -		unsigned int count;
> +		struct drm_i915_gem_request *request_count;
> +#define EXECLIST_COUNT_BITS 2
> +#define port_request(p) ptr_mask_bits((p)->request_count, EXECLIST_COUNT_BITS)
> +#define port_count(p) ptr_unmask_bits((p)->request_count, EXECLIST_COUNT_BITS)
> +#define port_pack(rq, count) ptr_pack_bits(rq, count, EXECLIST_COUNT_BITS)
> +#define port_unpack(p, count) ptr_unpack_bits((p)->request_count, count, EXECLIST_COUNT_BITS)

I haven't yet found anything more agreeable (unions and packing pointers
into a bitfield), so for the moment it remains an unsightly
request_count (although I still think it is safer to hint about its dual
purpose in the name).
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre